The present invention relates to ornamental structures and surfaces, more particularly to cast structures and surfaces, and most particularly to cast cement-based structures which have integral color patterns and to a method of making such structures and surfaces whereby control over the pattern is achieved to the degree of being reproducible from one casting to the next. The method of this invention is also readily adaptable to automated procedures.
There is a need to be able to create and control patterns in cement and plaster or gypsum based materials in both precast products and cast-on-site pieces. At present, the ability to create and control patterning in cement is extremely limited. Most commonly, if an attractive stone appearance is desired on a cement based material it is usually achieved by covering with a veneer of granite or marble.
Some of the disadvantages of marbles and granites which can be solved by this invention are lot-to-lot variation in color and pattern, limits in size due to costs of handling and transportation, difficulty in showing continuous patterns of marble veins, and cost. With regard to the problem of lot-to-lot variation and showing a continuous veining pattern, since marble and granite are natural materials, there is no control over the consistency of color and pattern from one piece to the next. It is often necessary to compare and match many different pieces to obtain a few which are sufficiently similar to be used to create a uniform appearance on a facing. As for size and cost, it is not practical to use marble in pieces larger than approximately four feet by eight feet.
The prior art is replete with methods to produce color and patterns in cast materials to simulate a natural stone appearance, such as marble or granite. However, in most instances there is little or no control over the pattern or its reproducibility. Furthermore, few, if any, of the prior art methods are readily adaptable to automation for consistent production of matching articles.
For example, U.S. Pat. No. 27,022, Lamb, discloses a method for manufacturing artificial marble in which balls of cement are mixed up to a consistency of paste and partially coated with dry paint. The balls are then placed in a mold and compressed causing the moisture within each ball to penetrate the dry material and consolidate into a single mass. The dry paint then appears as streaks on the surface of the article produced. This method is time consuming and requires precision on the part of the practitioner to achieve any degree of consistency from one piece to the next. Nor is it readily adaptable to an automated process.
U.S. Pat. No. 106,263, Frear, discloses the manufacture of artificial marble in which a solution of zinc sulphate, zinc chloride, sugar of lead, alum or salt is combined with a mixture of cement and silex to form a pasty mass having the consistency of mortar which is then cast in molds. By adding suitable colorants to the composition while it is in its plastic state or to the solution with which it is moistened, imitations of marble are obtained. Clearly, colorants added to the plastic mass would require some mixing to achieve a marble-like pattern, similar to the process used in mixing the two colors of a marble cake batter.
U.S. Pat. No. 134,300, Mellen, discloses a method of manufacturing artificial marble in which individual batches of cement of particular colors are prepared in separate vessels having small spouts. These are then individually poured into a mold in small streams in imitation of the veins of marble and the area between these streams filled in with cement of another color. Air is then blown across the mold to cause the colors to flow and mingle together until the desired effect is achieved. For finer veins, threads are dipped in colors and laid in the mold to be pulled through the cement after it is poured in. As with the Lamb patent, this method requires a degree of care and skill on the part of the practitioner to achieve any degree of consistency of pattern from one piece to the next.
U.S. Pat. No. 635,005, Summers, discloses artificial marble which is manufactured by mixing together lime-water and silicate of soda and adding a cement until it is fully incorporated. Pigments mixed with dry cement are then added and agitated into the mixture by stirring with a suitable tool. This mixture is then poured into a mold and allowed to set. This method, whereby pigment is merely stirred into a base mixture is the classic xe2x80x9cmarble cakexe2x80x9d method and is very difficult to control from one casting to the next.
U.S. Pat. No. 704,621, Czermak, discloses a process of manufacturing artificial marble in which cement, or the like, is spread upon a smooth surface and allowed to partially set to form a slab. A liquid mass of mortar, or similar substance, having a color corresponding to the color of the veins desired is poured over the slab which is then cracked through its entire thickness with a suitable instrument to slightly displace its component parts. The liquid mass enters the cracks and produces the artificial veins which penetrate from face to face of the slab. Since the shape and direction of cracking in the slab is dependent in part on the application of the instrument and in part on the structure of the slab itself, it is unlikely that a great degree of consistency in pattern can be achieved from one piece to the next using this method. In addition, since cracking of the slab disrupts the internal structure, this method has the added effect of weakening the slab.
U.S. Pat. No. 928,061, Mitats, discloses an artificial marble which comprises portland cement, marble dust, sand, a colorant and water which are mixed together and compressed in a mold. In this method, it is believed that the resulting product will be substantially of one color with the marble dust providing any variation which may be present.
U.S. Pat. No. 2,280,488, Jenkins, et al., discloses a method and apparatus for making a stone like unit in which batches of colored concrete are premixed and added in layers to a blending box. A mixing grid is drawn vertically through the layers at least once to mix them in a variation of the xe2x80x9cmarble cakexe2x80x9d method of the Summers patent. After the layers are blended in this manner, the mixture is poured from the box into a mold.
U.S. Pat. No. 5,248,338, Price discloses a colored marble concrete and a method of producing the same wherein a master mix of concrete of a desired primary color is prepared. Secondary or accent colors are added to the surface of the master mix within a container, such as a bucket, and are stirred to create a swirl pattern in the colors. The stirred mix is then poured into a mold. As with Summers, this the classic xe2x80x9cmarble cakexe2x80x9d method which is difficult to control from one casting to the next.
In contrast to the prior art, the present invention provides a method whereby color and pattern can be controlled and replicated across many castings to provide uniformity of color and pattern as well as, where desired, continuous veining from one piece to the next. The method of this invention is adaptable to any size of casting, both on and off-site, and to most means for transferring casting mixtures to a mold as well as to automated production systems for producing substantially consistent and identical articles.
The invention discussed herein provides one with the ability to create cement based cast articles which can be the equal in beauty of some of the finest marbles and granites, while having the advantages of cost, ability to control and replicate color and pattern, as well as the ability to be created as needed, cast on site, and created in any size desired.
On-site castings can be as large as desired, in theory 20 feet by 100 feet or larger. The cost advantages of being able to readily produce a surface having a controlled and reproducible pattern on-site versus the expense of selecting, cutting, shipping and erecting natural stone facings on a structure are readily evident.
Central to the invention is the ability to control creation of a pattern in a castable material. This ability to control the pattern also renders it reproducible from one casting to the next. This control is effected by means of the viscosity of a pouring mix, the geometric arrangement of two or more mixes prior to pouring, the placement of two or more mixes during pouring and the consolidation of the poured mix after placement. The present invention employs all of these means in a novel method whereby castable materials are geometrically arranged in a container according to a set formula or chart for a particular pattern and poured to produce patterned structures or surfaces wherein the pattern is consistent and reproducible each time the formula and pouring criteria are followed.
It is therefor an object of this invention to provide a method for creating multicolor designs and patterns in cast materials comprising the steps of:
a) preparing a mold to receive casting mixtures;
b) preparing at least two wet casting mixtures of different colors at a viscosity to facilitate controlled pouring thereof;
c) loading the casting mixtures into a holding container in a horizontal and vertical geometric arrangement according to a formula devised for a particular pattern;
d) transferring the loaded mixtures from the holding container to the mold, and;
e) consolidating the mixtures in the mold into a physically uniform mass and allowing the mass to set.
It is a further object to provide a method for casting multicolored cement based materials and controlling the patterning thereof, comprising:
a) preparing a mold to receive wet cements based materials;
b) preparing at least two wet cement based casting mixtures having different colors;
c) providing a holding container having a removable matrix subdividing the container into at least two subchambers;
d) loading the mixtures into the container in a geometric pattern according to the matrix and a repeatable formula devised therefor;
e) removing the matrix from the container and attaching a baffled pouring aperture to the container, and;
f) transferring the mixtures from the container to the mold through the pouring aperture whereby the baffled pouring aperture causes the mixtures to flow and combine in a predictable manner.
And it is a still further object of this invention to provide a method for producing reproducible colored and patterned cement based castings which simulate natural stone, comprising;
a) preparing two or more different colored wet cement based mixtures at a viscosity whereby the mixtures are pourable but resist combining when placed against each other;
b) loading the mixtures in a pouring container at geometrically determined positions both vertically and horizontally within the container and in specific amounts according to a formula corresponding to a particular pattern to be produced thereby forming a geometrically loaded bulk mix;
c) transferring the geometrically loaded bulk mix from the pouring container into a prepared form, and;
d) allowing the mixtures to set.